consoleapplet.java

计算机代数系统

package net.sf.yacas;


/*

Documentation for the applet, starting it here, but has to move to main docs:
just random thoughts for now.

1) typing 'restart' on the command line restarts the system
2) You can perform initialization calls by adding parameters "initN" in the html
   code, where N is a number from 1 upwards, which have to be in consecutive order.
3) add to the history with "historyN" parameters to the applet


<B>Note:</B> to allow supporting copy-pasting from and to this applet, you need to enable
access to the clip board on your computer. On Unix-style computers this can be done 
by appending the following lines to the file ~/.java.policy (create the file if it does
not exist yet):
<p>
<TT>
grant codeBase "http://www.xs4all.nl/~apinkus/*" {
permission java.awt.AWTPermission "accessClipboard";
};
</TT>
<p>
You can then copy with CTRL-c and paste with CTRL-v.


*/


import java.awt.datatransfer.Clipboard;
import java.awt.datatransfer.ClipboardOwner;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.StringSelection;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.awt.Toolkit;
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
import java.io.*;
import java.net.*;

public class ConsoleApplet extends Applet implements KeyListener, FocusListener, ClipboardOwner
{
  AppletOutput out;

  /// Applet initialization
  public void init() 
  {
    setBackground(Color.white);
    setLayout (null);
    addKeyListener(this);
    addFocusListener(this);

//    addMouseListener(this);

    out = new AppletOutput(this);
    ResetInput();
    
    String hintsfilename = getDocumentBase().toString() + ".hints";
    LoadHints(hintsfilename);
  }
  boolean focusGained = false;
  public void focusGained(FocusEvent evt) 
  {
    focusGained = true;
    inputDirty = true;
    outputDirty = true;
    repaint();
  }


  public void focusLost(FocusEvent evt) 
  {
  }

  public void lostOwnership(Clipboard clipboard, Transferable contents)
  {
  }

  LispOutput stdoutput = null;
  CYacas yacas = null;
  StringBuffer outp = new StringBuffer();
  public void start()
  {

    if (yacasLogo == null)
    {
      try
      {
        String fname = getDocumentBase().toString();
        int ind = fname.lastIndexOf("/");
        if (ind >0)
        {
          fname = fname.substring(0,ind+1)+"yacas.gif";
          yacasLogo = getImage(new URL(fname));
        }
      }
      catch (Exception e)
      {
      }
    }


    stdoutput = new StringOutput(outp);
    yacas = new CYacas(stdoutput);
    yacas.env.iCurrentInput = new CachedStdFileInput(yacas.env.iInputStatus);


    if (yacasLogo != null)
    {
      lines[currentLine] = new ImageLine(yacasLogo,this);
      currentLine = (currentLine+1)%nrLines;
    }

    {
      Font font = new Font("helvetica", Font.PLAIN, 12);
      Color c = new Color(96,96,96);

      AddLineStatic(100, "","", font, c);
      AddLineStatic(100, "","", font, c);

      AddLineStatic(100, "","This is Yacas version '" + CVersion.VERSION + "'.", font, c);

      AddLineStatic(100, "","Running from location '" + getDocumentBase() + "'.", font, c);

      AddLineStatic(100, "","Yacas is Free Software--Free as in Freedom--so you can redistribute Yacas or", font, c);
      AddLineStatic(100, "","modify it under certain conditions. Yacas comes with ABSOLUTELY NO WARRANTY.", font, c);
      AddLineStatic(100, "","See the GNU General Public License (GPL) for the full conditions.", font, c);
//TODO fixme    AddLineStatic(100, "","Type ?license or ?licence to see the GPL; type ?warranty for warranty info.", font, c);
      AddLineStatic(100, "","See http://yacas.sf.net for more information and documentation on Yacas.", font, c);
      AddLineStatic(100, "","Numeric mode: \""+BigNumber.NumericLibraryName()+"\"\n", font, c);
//TODO fixme    AddLineStatic(100, "","To exit Yacas, enter  Exit(); or quit or Ctrl-c.\n", font, c);
      AddLineStatic(100, "","", font, c);

      AddLineStatic(100, "","Type '?', '??' or 'help' for help, or type '?function' for help on a function.\n", font, c);
      AddLineStatic(100, "","Type 'restart' to restart Yacas, or 'cls' to clear screen.\n", font, c);
      AddLineStatic(100, "","To see example commands, keep typing 'Example();'\n", font, c);

    }

    {
      String docbase = getDocumentBase().toString();
      if (docbase.substring(0,4).equals("file"))
      {
        int pos = docbase.lastIndexOf("/");
        String zipFileName = docbase.substring(0,pos+1)+"scripts.zip";
        try
        {
        //  java.util.zip.ZipFile z = new java.util.zip.ZipFile(new File(new java.net.URI("file:/Users/ayalpinkus/projects/JavaYacas/tempscripts.zip")));
          java.util.zip.ZipFile z = new java.util.zip.ZipFile(new File(new java.net.URI(zipFileName)));
          LispStandard.zipFile = z;
//          out.println("Succeeded in finding "+zipFileName);
        }
        catch(Exception e)
        {
          out.println("Failed to find scripts.zip");
          out.println(""+zipFileName+" : \n");
          out.println(e.toString());
        //  return;
        }
      }
      if (docbase.startsWith("http"))
      {
        //jar:http://www.xs4all.nl/~apinkus/scripts.zip!/
        int pos = docbase.lastIndexOf("/");
        String scriptBase = "jar:"+ docbase.substring(0,pos+1)+"scripts.zip!/";
//        AddLineStatic(100, ""," '" + scriptBase + "'.", font, Color.red);
        yacas.Evaluate("DefaultDirectory(\""+scriptBase+"\");");
      }
      
    }


    try
    {
//      PerformRequest("Connected: version of engine is ","Atom(Version())");
      out.println("");
    }
    catch (Exception e)
    {
      out.println(e);
    } 

    int i;
    i=1;
    while (true)
    {
      String argn = "init"+i;
      String s = getParameter(argn);
      if (s == null) break;
      s = unescape(s);
      yacas.Evaluate(s);
      i++;
    }

    i=1;
    while (true)
    {
      String argn = "history"+i;
      String s = getParameter(argn);
      if (s == null) break;
      s = unescape(s);
      AppendHistoryLine(s);
//TODO remove      history[currentHistoryLine] = s;
//TODO remove      currentHistoryLine++;
      i++;
    }

    ResetInput();

  }
  public void stop()
  {
  }
  public void AppendHistoryLine(String line)
  {
    //TODO optimize! We need to wrap around the history buffer, this is inefficient.
    if (currentHistoryLine == nrHistoryLines)
    {
      int i;
      for (i=0;i<currentHistoryLine-1;i++)
      {
        history[i] = history[i+1];
      }
      currentHistoryLine--;
    }
    history[currentHistoryLine] = line;
    currentHistoryLine++;
  }

  private String unescape(String s)
  {
    StringBuffer buf = new StringBuffer();
    int i,nr=s.length();
    for(i=0;i<nr;i++)
    {
      if (s.charAt(i) == '\'' && s.charAt(i+1) == '\'')
      {
        buf.append('\"');
        i++;
      }
      else
      {
        buf.append(s.charAt(i));
      }
    }
    return buf.toString();
  }

  public void ResetInput()
  {
    if (inputLine.length()>0)
      if (inputLine.charAt(inputLine.length()-1) != '\\')
        gatheredMultiLine = "";
    inputLine = "";
    cursorPos = 0;
    historyBrowse = currentHistoryLine;
    inputDirty = true;
  }

  /// Applet destruction
	public void destroy()
  {
  }

  public void keyPressed(KeyEvent e)
  {
    processKeyEvent(e);
  }
  public void keyTyped(KeyEvent e)
  {
//    processKeyEvent(e);
  }
  public void keyReleased(KeyEvent e)
  {
//    processKeyEvent(e);
  }


  public void setClipboardContents( String aString )
  {
    StringSelection stringSelection = new StringSelection( aString );
    Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
    clipboard.setContents( stringSelection, this );
  }
  public String getClipboardContents() 
  {
    String result = "";
    Clipboard clipboard = Toolkit.getDefaultToolkit().getSystemClipboard();
    //odd: the Object param of getContents is not currently used
    Transferable contents = clipboard.getContents(null);
    boolean hasTransferableText = (contents != null) &&
                                  contents.isDataFlavorSupported(DataFlavor.stringFlavor);
    if ( hasTransferableText ) 
    {
      try 
      {
        result = (String)contents.getTransferData(DataFlavor.stringFlavor);
      }
      catch (java.awt.datatransfer.UnsupportedFlavorException ex)
      {
        //highly unlikely since we are using a standard DataFlavor
        System.out.println(ex);
      }
      catch (IOException ex) 
      {
        System.out.println(ex);
      }
    }
    return result;
  }

  protected void processKeyEvent(KeyEvent e)
  {
    inputDirty = true;

    if ((e.getModifiers() & InputEvent.CTRL_MASK) == InputEvent.CTRL_MASK)
    {
      if (KeyEvent.KEY_PRESSED != e.getID())
        return;
      if (e.getKeyCode() == (int)'C')
      {
        //out.println("Copy");
        setClipboardContents( gatheredMultiLine+inputLine );
      }
      else if (e.getKeyCode() == (int)'V')
      {
        try
        {
          String toInsert = getClipboardContents();
          if (toInsert != null)
          {
            int cr = toInsert.indexOf('\n');
            while (cr >= 0)
            {
              inputLine = inputLine+toInsert.substring(0,cr);
              toInsert = toInsert.substring(cr+1,toInsert.length());
              cr = toInsert.indexOf('\n');
//System.out.println("");
              AppendHistoryLine(inputLine);
//TODO remove              history[currentHistoryLine] = inputLine;
//TODO remove              currentHistoryLine++;
              AddLinesStatic(48,inputPrompt,inputLine);
              if (inputLine.charAt(inputLine.length()-1) == '\\')
                gatheredMultiLine = gatheredMultiLine + inputLine.substring(0,inputLine.length()-1);
              else
                PerformRequest("Out> ",gatheredMultiLine+inputLine);
              ResetInput();
            }
            inputLine = inputLine+toInsert;
            RefreshHintWindow();
            repaint();
            return;
          }
          //  out.println("Paste");
//          out.println(toInsert);
        }
        catch (Exception ex)
        {
        }
      }
      else
      {
        return;
      }
    }

    if (KeyEvent.KEY_PRESSED == e.getID())    
    {
      if (e.VK_SHIFT == e.getKeyCode()) {return;}
      if (e.VK_CONTROL == e.getKeyCode()) {return;}
      if (e.VK_ALT == e.getKeyCode()) {return;}
      else if (e.VK_HOME == e.getKeyCode())
      {
        cursorPos = 0;  
      }
/*Does not seem to work?
      else if (e.VK_COPY == e.getKeyCode())
      {
        System.out.println("COPY");
      }
      else if (e.VK_PASTE == e.getKeyCode())
      {
        System.out.println("PASTE");
      }
*/
      else if (e.VK_END == e.getKeyCode())
      {
        cursorPos = inputLine.length();  
      }
      else if (e.VK_LEFT == e.getKeyCode())
      {
        if (cursorPos>0) 
        {
          cursorPos--;  
          RefreshHintWindow();
          repaint();
          return;
        }
      }
      else if (e.VK_BACK_SPACE == e.getKeyCode())
      {
        if (cursorPos>0) 
        {
          cursorPos--;  
          inputLine = new StringBuffer(inputLine).delete(cursorPos,cursorPos+1).toString();
          RefreshHintWindow();
          repaint();
          return;
        }
      }
      else if (e.VK_ESCAPE == e.getKeyCode())
      {
        if (hintWindow != null)
        {
          hintWindow = null;
        }
        else
        {
          ResetInput();
        }
        repaint();
        return;
      }
      else if (e.VK_UP == e.getKeyCode())
      {
        {
          String prefix = inputLine.substring(0,cursorPos);
          int i = historyBrowse - 1;
          while (i > 0)
          {
            if (history[i].startsWith(prefix))
              break;
            i--;
          }
          if (i >= 0 && i != historyBrowse && history[i].startsWith(prefix))
          {
            historyBrowse = i;
            inputLine = history[historyBrowse];
          }
        }
      }
      else if (e.VK_DOWN == e.getKeyCode())
      {
        {
          String prefix = inputLine.substring(0,cursorPos);
          int i = historyBrowse + 1;
          while (i < currentHistoryLine)
          {
            if (history[i].startsWith(prefix))
              break;
            i++;
          }
          if (i < currentHistoryLine && history[i].startsWith(prefix))
          {
            historyBrowse = i;
            inputLine = history[historyBrowse];
          }
          else 
          {
            int pos = cursorPos;
            ResetInput();
            inputLine = prefix;
            cursorPos = pos;
          }
        }
      }
      else if (e.VK_RIGHT == e.getKeyCode())
      {
        if (cursorPos<inputLine.length()) 
        {
          cursorPos++;  
          RefreshHintWindow();
          repaint();
          return;
        }
      }
      else if (e.VK_ENTER == e.getKeyCode())
      {
        AppendHistoryLine(inputLine);
//TODO remove        history[currentHistoryLine] = inputLine;
//TODO remove        currentHistoryLine++;
        AddLinesStatic(48,inputPrompt,inputLine);
        if (inputLine.charAt(inputLine.length()-1) == '\\')
          gatheredMultiLine = gatheredMultiLine + inputLine.substring(0,inputLine.length()-1);
        else
          PerformRequest("Out> ",gatheredMultiLine+inputLine);
        ResetInput();
        RefreshHintWindow();
        repaint(0);
      }
      else
      {
        int c = (int)e.getKeyChar();
        if (c>=32 && c < 128)
        {
          inputLine = new StringBuffer(inputLine).insert(cursorPos,e.getKeyChar()).toString();
          cursorPos++;
          RefreshHintWindow();
        }
      }
      inputDirty=true;
      repaint();//0,getHeight()-2*fontHeight,getWidth(),2*fontHeight);
    }
  }
  void PerformRequest(String outputPrompt,String inputLine)
  {
    boolean succeed = false;
    if (inputLine.equals("restart"))
    {
      stop();
      int i;
      for (i=0;i<nrLines;i++) lines[i] = null;
      outputDirty = true;
      start();
      return;
    }
    else if (inputLine.equals("cls"))
    {
      int i;
      for (i=0;i<nrLines;i++) lines[i] = null;
      outputDirty = true;
      succeed = true;
    }
    else if (inputLine.equals("help") || inputLine.equals("?") || inputLine.equals("??"))
    {
      try
      {
        getAppletContext().showDocument( new URL("http://yacas.sourceforge.net/manindex.html"),"help");    
        succeed = true;
      }
      catch (Exception e)
      {
      }
    }
    else if (inputLine.charAt(0) == '?')
    {
      try
      {
        getAppletContext().showDocument( new URL("http://yacas.sourceforge.net/ref.html#"+inputLine.substring(1,inputLine.length())),"help");    
        succeed = true;
      }
      catch (Exception e)
      {
      }
    }
    else
    {
      outp.delete(0,outp.length());
      String response = yacas.Evaluate(inputLine);
      if (outp.length() > 0)
      {
        AddLinesStatic(48,"",outp.toString());
      }
      if (yacas.iError != null)
      {
        AddLinesStatic(48,"Error> ",yacas.iError);
      }
      AddLinesStatic(48, outputPrompt,response);
      succeed = true;
    }
    {
      if (!succeed) 
      {
        out.println("Request failed");